Email is a useful tool to transfer files from one person to another. Typically, files are attached to and delivered with the email message. In particular, the files may be sent as a separate message or, more commonly, attached to the content of the email in a single multipart message.
Given the storage capacity available on most computer systems, email messages and their attachments are often stored within an email system for long periods of time. Over time, the number of email messages and attachments can be difficult to manage. In particular, it is often difficult for a user to find an attached document in an email system, unless the user knows when the email message was sent or received, who sent or received the email message, or which folder stores the email message. Therefore, it can take a long time to search for attachments in an email system.
In some instances, conventional email systems allow a user to sort the email messages within the email system, or within a folder of the email system. Using such email message sorting functionality, a user might to try to find a document attached to one of the email messages. Some conventional email systems allow a user to group emails with attachments together at the beginning or end of a comprehensive list of emails in a folder. As a result, the emails without attachments are grouped at the other end of the email list. However, there is no sorting performed among the emails with attachments based on the characteristics of the attachments. The sorting is only based on the presence of an attachment. In a related manner, some conventional email systems implement a batch process to scan emails for attachments, remove the attachments from the emails, and save the attachments to a separate database. However, this type of batch process does not implement any further sorting based on the characteristics of the attachments, except to identify which emails have attachments.
Alternatively, if the user knows the approximate size of the attached document, then the user can sort the email messages by size and try to find the email message with the attached document the user is looking for. However, sorting email messages by size can still take a long time to find a particular attachment because each email message is separately opened and viewed to determine if the correct file is attached. Additionally, sorting emails by size can lead to inaccurate results because email message sorting depends on the total size of each email message. Since each email message may include multiple attachments, large embedded images, or compressed files, the total size of the email message is not necessarily indicative of the size of an attached file. Thus, an email list sorted according to size may combine emails with and without attachments.